I realise a lot of people enjoy Korean dramas these days, and the wave looks set to be strong for some time. Unless the competition buckles up. But nah. When I say 'competition', I refer to what I have grown up with: Singapore, Hong Kong and Taiwanese dramas. I don't have an opinion on Japanese dramas because I haven't watched enough to comment. As for mainland China dramas, well, they work sometimes, and it helps if you're a sinophile who likes history documentaries.
I'm always trying to pinpoint why Korean dramas tend to hit the sweet spot more than others. For myself, at least. But shall we just say, it's complicated. :) There are just so many good things I don't know where to start.
But one big difference I notice about Korean dramas viz-a-viz Singapore (i.e. Mediacorp) and Hong Kong TVB dramas is the number of shots the Koreans take for a one scene. It's their attention to detail and storytelling, really. Take Coffee Prince: a seaside scene of Hankyul looking longingly at Eunchan, the girl he loves (but mistakenly thinks is a guy). He reaches out to touch her hair (she's fast asleep) but shrinks back again, struggling with his emotions.
It doesn't take more than a few minutes. But the way they do it! First it's a scenic shot. Lets you build up an imagination of typical lovers' beaches in Korea. You see the meant-to-be lovers lying chastely next to each other on a mat. And they timed it perfectly, just the right pause so you have the context and can almost smell the sea salt sprays. It sets the mood and builds anticipation.
Next, the camera moves closer and you see his expression from a distance. Looking at her, he slowly reaches out to touch her hair (she's facing away from him). Then the camera angle changes completely. A close-up shot from the opposite side: you see her face now, and his hand lingering over her hair (his face is outside the camera's view). She's completely unaware and blissfully asleep, even scratching her arm absently now and then. The hand above her head trembles a little. And the camera pans out, this time showing him looking over her. Written all over his face is his love for her and his personal struggle (I don't think Mediacorp ever realised this, but good acting is important). And you just go "awww" inside.
Now, the reason I went to such lengths to describe the simple scene above is to highlight differences.
If the Taiwanese did it: He would verbalise his emotions instead of acting it out. So with his hand outstretched, he'll probably go, "Looking at you, my darling, I can feel my forbidden love for you grow! But I can't, I can't!" And to drive the final nail into the coffin of bad dramas, they will start playing a melodramatic Hokkien soundtrack that makes you wonder if you're in the wrong decade.
If the Hong Kongers did it: The whole thing would be over quite fast. Less shots, more economically done. But you will still get the gist of it, just not so conscious of the emotions in the actor. It's not so bad but you will feel a bit rushed, not having savoured the moment enough.
If the Singaporeans did it: Same economical style as the Hong Kongers, really, but with bad acting. So in the end, you wonder if he really loves her. Or worse, if she's actually pretending to be asleep. :D